The present invention relates to the field of diaphragm valve assemblies and, in particular, to diaphragm valve assemblies each varying in size but utilizing a diaphragm of a uniform size.
A conventional diaphragm valve assembly includes a valve housing having two fluid ports (a fluid inlet and a fluid outlet) and defining a valve chamber extending therebetween for fluid flow through the valve housing. The valve housing further includes an access port leading into the valve chamber. A bonnet covers the access port and includes an opening defined therein through which a valve stem arrangement slidably extends. The valve stem arrangement, in turn, includes a valve seat movably disposed between first and second positions within the valve chamber for sealing engagement with a fluid port in the first position (thereby defining a closed position of the valve assembly) and non-sealing engagement therewith in the second position (thereby defining an open position of the valve assembly).
As is conventional, a diaphragm is attached to and extends between the valve stem arrangement and the peripheral edge of the access port to seal the valve chamber from the access port. In particular, the diaphragm is retained in place by the disposition of its peripheral edge between the bonnet and the valve housing, the bonnet being clamped or otherwise forcibly retained in engagement with the valve housing by a bonnet nut, clamp, etc. In this conventional design, the valve stem arrangement and the diaphragm are exposed to the valve chamber and, in particular, to fluid flow therethrough, and together the valve stem arrangement and diaphragm effectively prevent fluid from leaking into and/or through the access port.
Examples of conventional diaphragm valves are disclosed in U.S. Pat. Nods. 5,954,086; 5,881,997; 5,771,884; 5,228,472; 4,750,709; 2,905,433; 2,784,934; 2,702,686; 2,665,105; 2,654,561; 2,653,788; 2,504,057; and 40,939. As disclosed in each of these references, the diaphragm completely covers and seals the valve chamber from the access port between the valve stem arrangement and the valve housing defining the valve chamber and fluid ports.
As a result of this conventional design for diaphragm valve assemblies, a change in the size of the fluid port necessitates a change in the size of the valve seat, which in turn leads to a change in the size of the access port through which the valve seat is inserted. This necessitates a change in the size of the diaphragm that covers and seals the valve chamber from the access port between the valve stem arrangement and the valve housing. As will therefore be appreciated by one having ordinary skill in the art, a number of varying sizes of parts must be manufactured and maintained in order to provide for varying sizes of diaphragm valve assemblies.
Accordingly, it is an object of the present invention to simplify the manufacturing and maintenance of diaphragm valve assemblies of varying sizes.
Briefly summarized, the diaphragm valve assembly of the present invention includes a valve housing having two fluid ports and defining both a valve chamber extending therebetween for fluid flow therethrough and an access port leading into the valve chamber. A bonnet covers the access port and defines an opening therein through which a valve stem arrangement extends. The valve stem arrangement includes a valve seat disposed within the valve chamber. The valve stem arrangement is slidable through the opening in the bonnet between a first position, wherein the valve seat is disposed in sealing engagement with a fluid port to thereby define a closed position of the valve assembly, and a second position, wherein the valve seat is disengaged from the first fluid port to thereby define an open position of the valve assembly. A diaphragm surrounds and is attached to the valve stem arrangement to form a seal therewith. In accordance with the present invention, the diaphragm valve assembly further includes a bonnet insert disposed about the diaphragm adjacent to the valve housing. The diaphragm forms a seal with an inner portion of the bonnet insert, and an outer portion of the bonnet insert forms a seal with the valve housing. The bonnet insert and the diaphragm together thereby prevent fluid flowing through the valve chamber from escaping into the access port between the valve housing and the valve stem arrangement.
In features of the present invention, the bonnet insert is directly exposed to fluid flowing through the valve chamber; an outer portion of the diaphragm is secured between the bonnet and the bonnet insert; an outer portion of the bonnet insert is secured between the bonnet and the valve housing; a clamp forcibly retains the bonnet to the valve housing; and the clamp retains the bonnet insert between the bonnet and the valve housing.
The present invention also includes the combination of two of the aforesaid diaphragm valve assemblies wherein the access ports are of different sizes but the diaphragms are identical in size. In features of this combination, the openings in the bonnet inserts are also identical in size; the bonnet inserts include inner diameters identical in size; and the vale stem arrangements include contoured diaphragm support members having identical contours.